Please Help! Engine Going To Reduced Power on Dyno, Only happens when o2 mV drops...

[Musky@RG]

Car is a 99 FRC Corvette with a 232/234 cam, intake, and full exhaust with stock injectors. So I've basically finished tuning the car, but randomly in the middle of the dyno pull it drops to a reduced power mode. When I look at the logs every time this happens the B2S1 o2 voltage drops from 960mV down to 80mV. The car is running open loop during full throttle but it seems to always happen when this occurs. Can the stock injectors be triggering some kind of ecu failsafe? The injector duty cycles are good in the midrange and hit 90% near redline.
Also whenever the reduced power mode occurs the AFR's go leaner by approximately .5 AFR.

Attached is a log of when it occurs at around 4400rpm
- I've added the tune file as well

[93camaro_zzz]

You should post up your tune file. Have you made any changes to the maximum airflow tables in the diagnostics section?

[POWERZONE]

Car is a 99 FRC Corvette with a 232/234 cam, intake, and full exhaust with stock injectors. So I've basically finished tuning the car, but randomly in the middle of the dyno pull it drops to a reduced power mode. When I look at the logs every time this happens the B2S1 o2 voltage drops from 960mV down to 80mV. The car is running open loop during full throttle but it seems to always happen when this occurs. Can the stock injectors be triggering some kind of ecu failsafe? The injector duty cycles are good in the midrange and hit 95% near redline.

Attached is a log of when it occurs at around 4400rpm:

Where is your wideband data? Also AFR error so you can judge what AFR is actually being achieved vs. the AFR commanded.

[Musky@RG]

You should post up your tune file. Have you made any changes to the maximum airflow tables in the diagnostics section?

Thanks for the reply. I've added the tune file to my original post so you can see the airflow tables I've modified. The only table I didn't touch in the diagnostics section is the (maximum delta airflow P0101)

[Musky@RG]

Where is your wideband data? Also AFR error so you can judge what AFR is actually being achieved vs. the AFR commanded.

There is no wideband on the car I'm tuning it on the dyno with a wideband. AFR commanded is all within .4 of an AFR from actual.

[Musky@RG]

Thanks for the replies, I've added the tune file to the original post.

[2xLS1]

It looks like it is just going lean on bank 2. If it was real reduced power mode you would see the throttle pulled back from 100%.IPW doesn't get reduced on that bank when it occurs. I would be looking for a problem with the fuel rail. Maybe a restriction in the crossover pipe or the passenger side rail that is limiting the fuel to that side under high demand.

[Musky@RG]

It looks like it is just going lean on bank 2. If it was real reduced power mode you would see the throttle pulled back from 100%.IPW doesn't get reduced on that bank when it occurs. I would be looking for a problem with the fuel rail. Maybe a restriction in the crossover pipe or the passenger side rail that is limiting the fuel to that side under high demand.

I will check it out tomorrow. I will keep you posted. Thanks